Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1996
Comparison of end-tidal PCO2 and average alveolar expired PCO2 during positive end-expiratory pressure.
The measurement of average alveolar expired PCO2 (PAECO2) weights each PCO2 value on the alveolar plateau of the CO2 expirogram by the simultaneous change in exhaled volume. PAECO2 can be determined from a modified analysis of the Fowler anatomic dead space (VDANAT). In contrast, end-tidal PCO2 (PETCO2) only measures PCO2 in the last small volume of exhalate. ⋯ This difference was significantly magnified during PEEP ventilation. The overestimation of PAECO2 by PETCO2 can result in a falsely high assessment of overall alveolar PCO2. Moreover, the use of PETCO2 to estimate alveolar PCO2 in the determination of the alveolar dead space fraction can result in falsely low and even negative values of alveolar dead space.
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Anesthesia and analgesia · Feb 1996
Randomized Controlled Trial Clinical TrialIntravenous lidocaine does not attenuate the cardiovascular and catecholamine response to a rapid increase in desflurane concentration.
This study was designed to investigate the effect of intravenous lidocaine on the sympathetic activity after a rapid increase in desflurane concentration. Twenty ASA grade I and II patients, were allocated randomly to a control group (C) and a lidocaine group (L). After induction of anesthesia with intravenous propofol 2 mg/kg and muscle relaxation with intravenous vecuronium 0.1 mg/kg, desflurane was given to achieve an end-tidal minimum alveolar anesthetic concentration (MAC) of 0.7 Group L received 1.5 mg/kg lidocaine intravenously, while Group C received an equal volume of 0.9% sodium chloride solution intravenously. ⋯ Plasma catecholamines were not significantly different between the groups. Intravenous lidocaine did not attenuate the sympathetic response to a rapid increase in desflurane concentration. It is unlikely that airway irritation is the cause of this phenomenon.
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Anesthesia and analgesia · Feb 1996
Randomized Controlled Trial Comparative Study Clinical TrialCompound motor action potential recording distinguishes differential onset of motor block of the obturator nerve in response to etidocaine or bupivacaine.
The purpose of this investigation was to establish an objective (quantitative) method for determining onset time of motor block induced by different local anesthetics. Twenty-four consenting patients undergoing transurethral surgery during spinal anesthesia were randomized to receive direct obturator nerve block with 10 mL of plain bupivacaine 0.5% (n = 12) or 10 mL of plain etidocaine 1% (n = 12). Another 14 patients (control group) received obturator nerve "block" with saline. ⋯ While CMAP amplitudes in the control group returned to their initial (baseline) values after 3-6 min, the patients receiving etidocaine or bupivacaine achieved > or = 90% motor blockade after 6 and 13 min, respectively. In the present report, the time to > or = 90% block was significantly faster in patients given etidocaine compared with those given bupivacaine. We conclude that electromyographic recording of CMAPs can be used to compare the ability of different local anesthetics to induce motor block.